Back to EveryPatent.com
United States Patent | 5,517,670 |
Allen ,   et al. | May 14, 1996 |
An adaptive data transfer channel providing means for a data management access method (AM) to define the channel subsystem data block transfer size and to transfer an extended data block (EDB) by a single channel transfer command to avoid repeated channel command word (CCW) command decode and status presentation operations. The adaptive scheme of this invention is transparent to the user and downwardly compatible with existing data record storage formats because it is independent of the user application program. The host software in the central processing complex (CPC) tests the peripheral data storage device (PDSD) to ensure compatibility with the EDB CCWs before selecting the channel program (CP) to be used for data block transfer in the subchannel. In the EDB format, the PDSD microcode permits the accumulation of logical data blocks (LDBs) from storage to form a single large EDB before transfer to the CPC responsive to a single transfer command. Conversely, the CPC can transfer a single EDB to the PDSD where it is parsed to form data records in an existing data record storage format, thus ensuring complete downward compatibility with existing data record storage formats.
Inventors: | Allen; Vincent K. (Tucson, AZ); Fry; Scott M. (Tucson, AZ); Harding; Warren B. (Tucson, AZ); Long; Robert G. (Tucson, AZ); Pence; Jerry W. (Tucson, AZ); Rhoten; Wayne E. (Morgan Hill, CA); Ripberger; Richard A. (Tucson, AZ) |
Assignee: | International Business Machines Corporation (Armonk, NY) |
Appl. No.: | 998971 |
Filed: | December 30, 1992 |
Current U.S. Class: | 710/30; 710/34; 710/35; 710/36; 710/65 |
Intern'l Class: | G06F 013/00 |
Field of Search: | 395/200,275,850,855,884,856,885 |
4148098 | Apr., 1979 | McCreight et al. | 364/200. |
4209841 | Jun., 1980 | Bambara et al. | 364/200. |
4210961 | Jul., 1980 | Whitlow et al. | 364/300. |
4414626 | Nov., 1983 | Arai et al. | 364/200. |
4417321 | Nov., 1983 | Chang et al. | 364/900. |
4445176 | Apr., 1984 | Burk et al. | 395/200. |
4616337 | Oct., 1986 | Sheth | 364/700. |
4703418 | Oct., 1987 | James | 364/200. |
4843544 | Jun., 1989 | DuLac | 364/200. |
4868742 | Sep., 1989 | Gant et al. | 364/200. |
5014194 | May., 1991 | Itoh | 364/200. |
5016160 | May., 1991 | Lambeth et al. | 364/200. |
5023829 | Jun., 1991 | Shibata | 364/900. |
5031091 | Jun., 1991 | Wakatasuki et al. | 364/200. |
5038277 | Aug., 1991 | Altman et al. | 364/200. |
5101477 | Mar., 1992 | Casper et al. | 395/250. |
5175817 | Dec., 1992 | Adams et al. | 395/200. |
5416907 | May., 1995 | Polzim et al. | 395/275. |
5459838 | Oct., 1995 | Cogarella et al. | 395/827. |
Foreign Patent Documents | |||
54-114134 | Sep., 1979 | JP. | |
55-74624 | Jun., 1980 | JP. | |
57-43221 | Mar., 1982 | JP. | |
1-302456 | Dec., 1989 | JP. |
"Method For Transferring Large Amounts of Data to Streaming Tapes" by Reser; IBM Tech. Discl. Bltn.; vol. 31 No. 6; Nov. 1988; pp. 341-342. "Computer Architecture and Parallel Processing"; Hwang et al; Memory & Input-Output Subsystems; McGraw Hill, New York; 1984; pp. 118-141. |